JP2021158001A - Battery module - Google Patents

Abstract

To provide a battery module in which the occurrence of electrical connection failure is suppressed.SOLUTION: A battery module 100 includes a housing 31, a plurality of battery cells 11 housed in the housing, a series bus bar 14 that connects one negative electrode terminal 12 and the other positive electrode terminal 13 of two battery cells that are lined up next to each other in the y direction, and a rigid portion 42 connected to the housing. The housing includes a first end wall 35 and a second end wall 36 that are separated in the y direction. These end walls are made of a resin material. The rigid portion has higher rigidity than this resin material and is connected to these end walls. The rigid portion has a longer length Lz in the z direction than the length Lx in the x direction.SELECTED DRAWING: Figure 12

Description

The disclosure described herein relates to a battery module comprising a plurality of battery cells.

As shown in Patent Document 1, a battery module in which a plurality of unit batteries are housed in a case is known.

Japanese Patent No. 4834376

In the battery module described in Patent Document 1, when the unit battery expands, the case tends to expand accordingly. As a result, the relative positions of the plurality of unit batteries in the case may fluctuate.

A plurality of unit batteries are electrically connected via a conductive member or the like. However, if the relative positions of the plurality of unit batteries fluctuate as described above, there is a risk that an electrical connection failure may occur between the unit batteries and the conductive member.

An object of the present disclosure is to provide a battery module in which the occurrence of electrical connection failure is suppressed.

The battery module according to one aspect of the present disclosure includes an insulating housing (31) including a bottom wall (33) and an annular wall (34) that rises from the bottom wall in an annular shape.
Each of the electrode terminals (12, 13) formed in the battery case in which the power generation element is housed is provided, and the electrode terminals are located on the tip side of the annular wall with respect to the bottom wall in the standing direction of the annular wall. A plurality of battery cells (11) housed in an insulating housing in such a manner that they are arranged in an arrangement direction orthogonal to the direction, and
A connection unit (14) that electrically connects the electrode terminals of each of the plurality of battery cells,
It has a rigid portion (42) connected to an annular wall, and has.
The annular wall is separated from the first end wall (35) and the second end wall (36) in the alignment direction, and in the lateral direction orthogonal to the standing direction and the alignment direction, and is separated from the first end wall and the second end. It has a first side wall (37) and a second side wall (38) that connect to the wall.
The forming material for each of the first end wall and the second end wall is a resin material.
The rigid portion has higher rigidity than the resin material, and the length in the upright direction is longer than the length in the lateral direction.

According to this, it is suppressed that the tip side separated from the bottom wall (33) is deformed in the line-up direction in each of the standing directions of the first end wall (35) and the second end wall (36). Therefore, it is possible to prevent the electrode terminals (12, 13) of each of the plurality of battery cells (11) arranged in the arrangement direction from being displaced in the arrangement direction. As a result, the action of stress on the connection portions of the electrode terminals (12, 13) at the connection portion (14) is suppressed. It is possible to prevent electrical connection failure between the connection portion (14) and the electrode terminals (12, 13).

The reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope at all.

It is a perspective view which shows the appearance structure of a battery module. It is a perspective view which shows the appearance structure of a battery module. It is an exploded perspective view which shows the internal structure of a battery module. It is an exploded perspective view which shows the internal structure of a battery module. It is a top view of the housing. It is a side view of a housing. It is a top view of the housing in which the battery cell is housed. It is a side view of the housing in which a battery cell is housed. It is an end view of the housing in which the battery cell is housed. It is a top view for demonstrating the storage state of a battery cell in a housing. It is sectional drawing for demonstrating the storage state of a battery cell in a housing. It is sectional drawing for demonstrating the storage state of a battery cell in a housing. It is an end view for demonstrating the modification of the connecting part. It is a figure for demonstrating the deformation example of a rigid part.

Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each form, the same reference numerals may be attached to the parts corresponding to the matters described in the preceding forms, and duplicate explanations may be omitted. When only a part of the configuration is described in each form, the other forms described above can be applied to the other parts of the configuration.

It is possible to combine the parts that clearly indicate that the combination is possible in each embodiment. Further, if there is no particular problem in the combination, it is possible to partially combine the embodiments, the embodiments and the modified examples, and the modified examples with each other even if it is not clearly stated that the combination is possible. be.

(First Embodiment)
The battery module according to this embodiment will be described with reference to FIGS. 1 to 12. The battery module of this embodiment is applied to an electric vehicle such as an electric vehicle or a plug-in hybrid vehicle.

Note that FIGS. 10 to 12 schematically show the battery module. FIG. 10 corresponds to FIG. 7, a part thereof is shown, and a series bus bar 14 described later is added. FIG. 11 corresponds to a cross section along the XI-XI line shown in FIG. 7, a part thereof is shown, and one series bus bar 14 is added. FIG. 12 corresponds to the cross section along the line XII-XII shown in FIG.

In the following, the three directions orthogonal to each other are referred to as the x direction, the y direction, and the z direction. In the drawings, the description of "direction" is omitted, and they are simply shown as x, y, and z. The x direction corresponds to the lateral direction. The y direction corresponds to the alignment direction. The z direction corresponds to the standing direction.

<In-vehicle battery>
The battery module 100 is shown in FIGS. 1 and 2. A plurality of battery modules 100 are mounted on the vehicle. A plurality of battery modules 100 are connected in series or in parallel by a wire harness or the like. This constitutes an in-vehicle power supply. The in-vehicle power supply functions to supply electric power to various electric loads mounted on the vehicle. An in-vehicle power supply may be configured by one battery module 100.

A vehicle duct is connected to the battery module 100. A fluid for adjusting the temperature of a plurality of battery cells 11 included in the battery module 100 is supplied from this duct. As a result, an excessive temperature change of the battery cell 11 is suppressed.

As the location of the in-vehicle power supply, for example, a space under the front seat of the vehicle, a space under the rear seat, a space between the rear seat and the trunk room, and the like can be appropriately adopted.

<Battery module>
As shown in FIGS. 3 and 4, the battery module 100 has a battery stack 10, a case 30, a monitoring unit 50, and a cover 70. The battery stack 10 is stored in the storage space of the case 30. The monitoring unit 50 is provided outside the case 30. The cover 70 is connected to the case 30 so as to cover the monitoring unit 50.

The battery stack 10 has a plurality of battery cells 11 arranged in the y direction. The arrangement of these plurality of battery cells 11 in the y direction is held by the case 30.

The case 30 has a housing 31 having an opening and a lid 32 fixed to the housing 31 in a manner of closing the opening. The housing 31 is formed with a plurality of slits 34f for communicating the storage space formed by the housing 31 and the lid 32 and the space outside the storage space (external space). The fluid supplied from the duct flows into the storage space through the slit 34f. The fluid flowing through the storage space flows out of the storage space through the slit 34f.

The lid 32 is formed with a plurality of openings for exposing the negative electrode terminals 12 and the positive electrode terminals 13 of the plurality of battery cells 11 to the outside of the storage space. A series bus bar 14 is provided on the outer wall of the lid 32 so as to close the opening. The series bus bar 14 is joined to one of the negative electrode terminals 12 of the two battery cells 11 arranged adjacent to each other in the y direction and the other positive electrode terminal 13. As a result, the plurality of battery cells 11 are electrically connected in series via the series bus bar 14.

Of the plurality of battery cells 11 connected in series, the negative electrode terminal 12 of the battery cell 11 having the lowest potential and the positive electrode terminal 13 of the battery cell 11 having the highest potential are also exposed from the opening of the lid 32. The negative electrode connection terminal 15 is connected to the negative electrode terminal 12. The positive electrode connection terminal 16 is connected to the positive electrode terminal 13. As shown in FIGS. 1 and 2, a part of each of the negative electrode connection terminal 15 and the positive electrode connection terminal 16 is located outside the cover 70.

Further, the lid 32 is provided with a plurality of voltage detection lines for detecting the output voltages of the plurality of battery cells 11. One end of each of the plurality of voltage detection lines is connected to each of the plurality of series bus bars 14, the negative electrode connection terminal 15, and the positive electrode connection terminal 16. The other ends of the plurality of voltage detection lines are grouped into a sensor connector.

Further, the lid 32 is provided with a temperature sensor that detects the temperature of the battery stack 10. The temperature sensor has a thermistor contacted with at least one of a plurality of battery cells 11 constituting the battery stack 10 and a temperature detection line connected to one end of the thermistor. The other end of the temperature detection line is grouped together with the other ends of the plurality of voltage detection lines in the sensor connector. From the voltage detection line and the temperature detection line, an analog signal as a detection result indicating the output voltage of the battery cell 11 and the temperature of the battery stack 10 is input to the monitoring unit 50.

The monitoring unit 50 has a circuit board 51, a first connector 52, and a second connector 53. The circuit board 51 includes a printed circuit board, a high-voltage circuit section, a low-voltage circuit section, and an insulating circuit section. The first connector 52, the second connector 53, the high-voltage circuit section, the low-voltage circuit section, and the insulation circuit section are each mounted on the printed circuit board.

A sensor connector is electrically connected to the first connector 52 via a wire harness. An external battery ECU is electrically connected to the second connector 53 via a wire harness.

The high voltage circuit unit is electrically connected to the first connector 52. The low voltage circuit section is electrically connected to the second connector 53. The isolated circuit section functions to transmit and receive signals to and from each other while electrically insulating the high voltage circuit section and the low voltage circuit section.

The high voltage circuit unit has a monitoring IC chip. The monitoring IC chip converts the analog signal as the detection result input from the sensor unit into a digital signal. The isolated circuit section outputs the digital signal input from the high voltage circuit section to the low voltage circuit section. The low voltage circuit section has a microcomputer for communication. The microcomputer outputs a digital signal as a detection result input from the insulation circuit unit to the battery ECU by communicating with the battery ECU.

The battery ECU determines the equalization of SOCs of each of the plurality of battery cells 11 based on the input voltage and temperature detection results. Then, the battery ECU outputs an instruction for equalization processing based on the determination to the monitoring unit 50. This instruction signal is input to the monitoring IC chip of the high voltage circuit section via the low voltage circuit section and the insulation circuit section.

The monitoring IC chip includes a switch for selectively charging and discharging the battery cell 11 by connecting at least two negative electrode terminals 12 of the plurality of battery cells 11 and the positive electrode terminals 13 to each other. .. The monitoring IC chip controls the opening and closing of the switch according to the instruction input from the battery ECU. As a result, a part of the plurality of battery cells 11 is individually charged and discharged. As a result, the SOCs of the plurality of battery cells 11 are equalized. SOC is an abbreviation for state of charge.

The cover 70 is connected to the case 30 in a manner in which the cover 70 faces the outer wall of the lid 32 while being separated in the z direction. A space is formed between the cover 70 and the lid 32 by this connection. A series bus bar 14, a part of the negative electrode connection terminal 15 and the positive electrode connection terminal 16, a sensor unit, and a monitoring unit 50 are provided in this space. These are covered by a cover 70.

The cover 70 is formed with an opening for exposing the second connector 53 to the outside of the space between the cover body 32 and the cover 70. The connector of the wire harness can be inserted and removed from the second connector 53 through this opening. As the connection between the cover 70 and the case 30, for example, a snap fit can be adopted.

<Battery stack>
As described above, the battery stack 10 has a plurality of battery cells 11 arranged in the y direction. The battery cell 11 is a secondary battery that generates an electromotive voltage by a chemical reaction. Specifically, as the battery cell 11, a lithium ion battery, a nickel hydrogen secondary battery, an organic radical battery, or the like can be adopted.

Each of the plurality of battery cells 11 has a power generation element and a metal battery case for accommodating the power generation element. The power generation element includes a negative electrode, a separator, a positive electrode, and an electrolytic solution. The negative electrode and the positive electrode are laminated via a separator. These three layers are wet with the electrolytic solution. The separator has the property of allowing electrons to pass through but not molecules. Electrons (current) flow between the negative electrode and the positive electrode via the separator.

The power generation element is charged and discharged by a redox reaction. The power generation element generates a gas such as hydrogen by this redox reaction. In addition, the electrolytic solution generates gas due to deterioration over time. The battery cell 11 tends to expand due to the generation of this gas.

The battery case has a flat shape with a thin thickness in the y direction. The battery case has a shorter length in the z direction than a length in the x direction. As the battery case, a shape in which the length in the z direction is longer than the length in the x direction or a shape in which the lengths in these two directions are the same can be adopted.

The battery case has a square pillar shape. Therefore, the battery case (battery cell 11) has six surfaces. The battery cell 11 has an upper surface 11a and a lower surface 11b arranged in the z direction. The battery cell 11 has a first main surface 11c and a second main surface 11d arranged in the y direction. The battery cell 11 has a first horizontal surface 11e and a second horizontal surface 11f arranged in the x direction.

Of the six surfaces included in the battery cell 11, the first main surface 11c and the second main surface 11d have a larger area than the other four surfaces. Therefore, the battery cell 11 tends to expand in such a manner that the first main surface 11c and the second main surface 11d are separated from each other in the y direction. More specifically, the battery cell 11 tends to expand in the y direction with the midpoint CP in the x and z directions on the main surface as the apex. The positions of the midpoint CP in the x-direction and the z-direction are equivalent to the positions of the geometric center of the battery cell 11 in the x-direction and the z-direction.

A negative electrode terminal 12 and a positive electrode terminal 13 are formed on the upper surface 11a of the battery cell 11. The negative electrode terminal 12 and the positive electrode terminal 13 are arranged in the x direction. The negative electrode terminal 12 is located on the first horizontal surface 11e side. The positive electrode terminal 13 is located on the second horizontal surface 11f side.

The two battery cells 11 arranged adjacent to each other in the y direction face each other with the first main surface 11c facing each other and the second main surface 11d facing each other. As a result, one of the negative electrode terminals 12 and the other positive electrode terminal 13 of the two battery cells 11 arranged adjacent to each other are arranged in the y direction. As a result, the battery stack 10 is composed of two electrode terminal groups in which the negative electrode terminals 12 and the positive electrode terminals 13 are alternately arranged in the y direction.

The negative electrode terminals 12 and the positive electrode terminals 13 included in these electrode terminal groups and arranged adjacent to each other in the y direction are electrically connected via a series bus bar 14, for example, as shown in FIG. As a result, the plurality of battery cells 11 constituting the battery stack 10 are electrically connected in series. The negative electrode terminal 12 and the positive electrode terminal 13 correspond to the electrode terminals. The series bus bar 14 corresponds to the connection portion.

Due to the electrical connection configuration shown above, the plurality of battery cells 11 are arranged in the y direction in the order of potential. The lowest potential battery cell 11 is located on one side of both ends of the plurality of battery cells 11 arranged in the y direction. The battery cell 11 having the highest potential is located on the other side of both ends of the plurality of battery cells 11 arranged in the y direction. The negative electrode connection terminal 15 shown in FIG. 1 is connected to the negative electrode terminal 12, and the positive electrode connection terminal 16 shown in FIG. 2 is connected to the positive electrode terminal 13.

As described above, the battery cell 11 expands in the y direction due to the generation of gas. As a result, the relative positions of the negative electrode terminals 12 and the positive electrode terminals 13 arranged adjacent to each other in the y direction may be displaced in the y direction. The series bus bar 14 has a shape that is easily deformed in the y direction so as to correspond to this displacement.

<Series bus bar>
As schematically shown in FIGS. 10 and 11, the series bus bar 14 has two terminal conductive portions 17 and one connecting conductive portion 18 in a subdivided manner. Two terminal conductive portions 17 arranged apart from each other in the y direction are integrally connected via one connecting conductive portion 18.

The terminal conductive portion 17 has a flat plate shape having a thin thickness in the z direction. The thickness of the terminal conductive portion 17 is determined so that during laser welding of the terminal conductive portion 17 and the electrode terminal of the battery cell 11, it is possible to avoid raising the temperature so that the performance of the battery cell 11 is changed by the laser. There is.

The connecting conductive portion 18 extends in a manner of being separated from one of the two terminal conductive portions 17 in the z direction, then folds back and extends in the z direction toward the other of the two terminal conductive portions 17. Due to this shape, the connecting conductive portion 18 has a property of being easily deformed in the y direction in which the two terminal conductive portions 17 are lined up.

The length between the two terminal conductive portions 17 of the connecting conductive portion 18 is, by design, the gap between the plurality of battery cells 11 housed in the case 30 and the gap between the battery cells 11 and the case 30 in the y direction. It is longer than the total president.

<Case>
As described above, the case 30 has a housing 31 and a lid 32. The housing 31 and the lid 32 are each made of an insulating resin material. The melting point of this resin material is higher than the melting point of the separator contained in the power generation element.

As shown in FIGS. 5 and 6, the housing 31 has a box shape that opens in the z direction and has a bottom. The housing 31 has a bottom wall 33 having a thin thickness in the z direction, and an annular wall 34 that rises in an annular shape from the edge of the inner bottom surface 33a of the bottom wall 33. The opening of the housing 31 is partitioned by the tip end side of the annular wall 34. The housing 31 corresponds to an insulating housing.

Described in detail, the annular wall 34 has a first end wall 35 and a second end wall 36 which are arranged apart from each other in the y direction, and a first side wall 37 and a second side wall 38 which are arranged apart from each other in the x direction. The first end wall 35, the first side wall 37, the second end wall 36, and the second side wall 38 are sequentially connected in an annular direction in the circumferential direction around the z direction.

Bolt holes 34a for bolting the lid 32 are formed on each of these four walls. The lid 32 is bolted to the housing 31 in a manner that closes the opening of the housing 31. This constitutes a storage space.

A negative electrode output terminal 34b for connecting and fixing the negative electrode connection terminal 15 and the terminal of the wire harness is insert-molded on the outside of the storage space in the first end wall 35. A positive electrode output terminal 34c for connecting and fixing the positive electrode connection terminal 16 and the terminal of the wire harness is insert-molded on the outside of the storage space in the second end wall 36.

These output terminals are bolt shafts, the heads of which are embedded in the end walls. The shaft portion of the output terminal extends from the bottom wall 33 toward the opening of the housing 31. A hole formed at the end of the connection terminal is passed through the shaft portion, and a hole formed at the terminal of the wire harness is passed through the shaft portion. Then, a nut is fastened to this shaft portion. As a result, the connection terminal and the terminal of the wire harness are electrically connected. Strictly speaking, the head of the output terminal is insert-molded into the connecting portion 43 described later.

Each of the first side wall 37 and the second side wall 38 is formed with a plurality of slits 34f that open to the inner side surface 34d on the storage space side and the outer side surface 34e on the back side thereof. The slits 34f formed on the first side wall 37 and the slits 34f formed on the second side wall 38 are aligned in the x direction. A plurality of slits 34f are arranged in the y direction at predetermined intervals on each of the first side wall 37 and the second side wall 38.

<Mouth>
As shown in FIGS. 2 and 5, the housing 31 has a mouth portion 39 in addition to the bottom wall 33 and the annular wall 34 described above. The mouth 39 is for attaching and fixing the duct to the battery module 100.

The mouth portion 39 is formed on the outer surface 34e of the first side wall 37. The mouth portion 39 stands up in the x direction from the outer surface 34e so as to be separated from the storage space of the case 30. The mouth 39 extends annularly on the outer surface 34e. The opening on the outer surface 34e side of all the slits 34f formed in the first side wall 37 is surrounded by the mouth portion 39. The duct is attached and fixed to the mouth portion 39 in such a manner that the hollow partitioned by the mouth portion 39 and the supply passage of the duct communicate with each other.

<Groove>
As shown in FIG. 5, a plurality of groove portions 34g extending in the z direction are formed on the inner side surfaces 34d of each of the first side wall 37 and the second side wall 38 of the annular wall 34. The groove portion 34g is formed on the bottom wall 33 side of the slit 34f and the opening side of the housing 31 on these side walls.

The space for partitioning each of the groove portion 34g on the bottom wall 33 side and the groove portion 34g on the opening side of the housing 31 communicates with the hollow partitioning of the slit 34f in the z direction. The groove portion 34g on the side of the plurality of bottom walls 33 and the groove portion 34g on the side of the plurality of openings are arranged in the y direction at predetermined intervals on the first side wall 37 and the second side wall 38, respectively, in the same manner as the plurality of slits 34f. I'm out.

<Septum>
As shown in FIG. 5, the housing 31 has a plurality of partition walls 40 in addition to the bottom wall 33, the annular wall 34, and the mouth portion 39 described above. These plurality of partition walls 40 have a flat plate shape having a thin thickness in the y direction. The partition wall 40 having such a shape is inserted into the groove portion 34g of the first side wall 37 and the groove portion 34g of the second side wall 38 arranged in the x direction. Each of the plurality of partition walls 40 is arranged in the y direction with a predetermined interval in the same manner as the plurality of groove portions 34g.

Each of the plurality of partition walls 40 inserted into each of the plurality of groove portions 34g is aligned with each of the plurality of slits 34f in the x direction. The partition wall 40 is located between the slit 34f formed on the first side wall 37 and the slit 34f formed on the second side wall 38 in the x direction.

The thickness of the partition wall 40 in the y direction is thinner than the length of the slit 34f in the y direction. Therefore, it is avoided that the partition wall 40 closes all the openings on the inner side surface 34d side of the slit 34f. The opening on the inner side surface 34d side of the slit 34f is divided into two in the y direction by the partition wall 40.

The storage space of the housing 31 is divided into a plurality of arrangement spaces by a plurality of partition walls 40. Specifically, the storage space of the housing 31 is between the first end wall 35 and the partition wall 40, between the two partition walls 40 arranged adjacent to each other in the y direction, and between the partition wall 40 and the second end wall 36. It is partitioned in the configuration space between. Battery cells 11 are provided in each of these plurality of arrangement spaces.

<Distribution channel>
Each of the plurality of battery cells 11 is provided in the above-mentioned arrangement space in such a manner that its lower surface 11b approaches the inner bottom surface 33a. As shown in FIGS. 7 to 9, the upper surface 11a side of the battery cell 11 is located outside the housing 31 in a state where the battery cell 11 is provided in the arrangement space. Outside the housing 31, the main surfaces of the two battery cells 11 arranged adjacent to each other in the y direction are opposed to each other and separated from each other.

On the other hand, in the housing 31, the two battery cells 11 arranged adjacent to each other in the y direction are arranged in the y direction via one partition wall 40. The main surface of the battery cell 11 and the partition wall surface 40a facing the y-direction of the partition wall 40 face each other while being separated from each other. A gap is formed between the battery cell 11 and the partition wall 40.

The gap between the battery cells 11 arranged adjacent to each other in the y direction and the partition wall 40 is between the slit 34f formed on the first side wall 37 and the slit 34f formed on the second side wall 38 in the x direction. positioned. These two slits 34f and the void form a flow path for the fluid to pass through the storage space.

The fluid supplied from the duct flows into the storage space through the slit 34f formed in the first side wall 37. This fluid passes through the main surface of the battery cell 11 which forms part of the void. As a result, heat exchange is performed between the fluid and the battery cell 11. The fluid that has exchanged heat with the battery cell 11 flows out of the storage space through the slit 34f formed in the second side wall 38.

<Protrusion>
As shown in FIG. 11, each of the two partition wall surfaces 40a included in the partition wall 40 is formed with minute protrusions 41 that locally project in the y direction. A minute protrusion 41 that locally protrudes in the y direction is also formed on the inner end surface 34h on the storage space side of each of the first end wall 35 and the second end wall 36. Further, minute protrusions 41 that locally protrude in the x direction are formed on the inner side surfaces 34d of the first side wall 37 and the second side wall 38.

As schematically shown in FIG. 11, these plurality of protrusions 41 extend from the inner bottom surface 33a side toward the opening side of the housing 31 in the z direction. The tip surface of the protrusion 41 on the opening side of the housing 31 is sharpened. The tip end side of the protrusion 41 has a tapered shape as it approaches the opening of the housing 31.

<Press fit>
Each of the plurality of battery cells 11 is press-fitted into the above-mentioned arrangement space in such a manner that its lower surface 11b approaches the inner bottom surface 33a. By this press-fitting, the protrusion 41 that locally protrudes in the y direction comes into contact with the lower surface 11b of each of the first main surface 11c and the second main surface 11d of the battery cell 11. At the same time, the partition wall 40 and the protrusion 41 formed on the end wall are deformed in a manner of contracting in the z direction and the y direction. Similarly, the protrusion 41 that locally protrudes in the x direction comes into contact with the lower surface 11b of each of the first horizontal surface 11e and the second horizontal surface 11f of the battery cell 11. At the same time, the protrusion 41 formed on the side wall is deformed in a manner of contracting in the z direction and the x direction.

Due to the above-mentioned deformation due to press fitting, the partition wall 40 and the protrusion 41 of the end wall generate a restoring force in the z direction and the y direction. The protrusion 41 on the side wall generates a restoring force in the z direction and the x direction. As shown in FIGS. 10 and 11, the restoring force of the protrusions 41 keeps the plurality of battery cells 11 aligned in the y direction in the storage space. Each of the plurality of battery cells 11 is sandwiched by the protrusion 41 in the storage space of the case 30.

The partition wall 40 and the protrusion 41 formed on the end wall are in contact with the first horizontal surface 11e side and the second horizontal surface 11f side on the main surface of each of the plurality of battery cells 11. More specifically, the protrusion 41 is in contact with an electrode terminal on the lower surface 11b side of the main surface of each of the plurality of battery cells 11 and a portion having a position equivalent to that in the y direction.

<Rigid part>
As shown in FIGS. 10 to 12, the rigid portion 42 is integrally connected to the back surface side of the inner end surface 34h of each of the first end wall 35 and the second end wall 36. The rigid portion 42 is made of a metal material such as SUS, which has higher rigidity than each of the first end wall 35 and the second end wall 36.

The rigid portion 42 has a tubular shape with the z direction as the axial direction. The rigid portion 42 has a shape in which the length Lz in the z direction is longer than the length Lx in the x direction. The rigid portion 42 extends continuously between the bottom wall 33 and the opening of the housing 31 in the z direction.

The outer ring surface of the rigid portion 42 is covered with an insulating resin material that constitutes the end wall of the housing 31. On the other hand, the inner ring surface of the rigid portion 42 is not covered with this resin material, and the shaft portion of the bolt can be inserted into the hollow portion thereof. A shaft portion of a bolt for connecting and fixing the battery module 100 to the vehicle body is passed through the hollow of the rigid portion 42.

As shown in FIG. 11, the bottom wall 33 side of the rigid portion 42 is aligned with the tip end side of the protrusion 41 in the y direction. The intermediate portion between the bottom wall 33 and the opening of the rigid portion 42 is aligned with the portion of the battery cell 11 that passes through the midpoint CP and the center line CL orthogonal to the z direction in the y direction. The opening side of the rigid portion 42 is aligned with the portion of the battery cell 11 between the center line CL and the upper surface 11a in the y direction.

In the present embodiment, two rigid portions 42 are integrally connected to each of the first end wall 35 and the second end wall 36. As shown in FIG. 12, these two rigid portions 42 are separated from each other in the x direction.

As shown by the alternate long and short dash line in FIG. 10, a plurality of negative electrode terminals 12 and positive electrode terminals 13 are alternately arranged in the y direction on the first side wall 37 side of the housing 31, thereby forming a first electrode terminal group. There is. Similarly, a plurality of negative electrode terminals 12 and positive electrode terminals 13 are alternately arranged in the y direction on the second side wall 38 side of the housing 31, thereby forming a second electrode terminal group. In each of these electrode terminal groups, a series bus bar 14 is electrically and mechanically connected to one negative electrode terminal 12 and one positive electrode terminal 13 that are adjacent to each other in the y direction.

As shown in FIGS. 10 and 12, the position of one of the two rigid portions 42 in the x direction is equivalent to the position of the first electrode terminal group in the x direction. The position of the other of the two rigid portions 42 in the x direction is equivalent to the position of the second electrode terminal group in the x direction.

Due to this positional relationship, the batteries of the plurality of battery cells 11 are located between the rigid portion 42 integrally connected to the first end wall 35 and the rigid portion 42 integrally connected to the second end wall 36. A portion of the case that has a position equivalent to that of the electrode terminal in the y direction is located. The protrusion 41 that contacts the main surface of the equivalent portion at the y-direction is a rigid portion that is integrally connected to the first end wall 35 and a rigid portion that is integrally connected to the second end wall 36. It is located between 42 and 42.

<Connecting part>
As shown schematically in FIGS. 10 and 12 surrounded by an alternate long and short dash line, a connection for increasing the connection strength of the two rigid portions 42 is provided on the back surface side of each of the first end wall 35 and the second end wall 36. The portions 43 are integrally connected. The connecting portion 43 extends from one of the two rigid portions 42 to the other to connect the two. The connecting portion 43 increases the thickness of the portion between the two rigid portions 42 of each of the first end wall 35 and the second end wall 36 in the y direction. The strength of the connecting portion between the rigid portion 42 and the connecting portion 43 in each of the first end wall 35 and the second end wall 36 is improved.

The connecting portion 43 of the present embodiment extends in the x direction and extends in the z direction between the two rigid portions 42. The connecting portion 43 is aligned with the midpoint CP of the battery cell 11 and the portion of the battery cell 11 passing through the center line CL in the y direction. Further, the connecting portion 43 has a shape in which the length in the z direction is longer than the length in the x direction. The overall shape of the composite body in which the connecting portion 43 and the two rigid portions 42 connected by the connecting portion 43 are combined is shorter in the z direction than the length in the x direction.

The connecting portion 43 is located outside the storage space together with the rigid portion 42. The head of the output terminal described above is insert-molded in the connecting portion 43. The shaft portion of the output terminal projects in the z direction from the upper surface 43a on the opening side of the housing 31 of the connecting portion 43.

<Issue>
As described in this embodiment, the battery cell 11 expands in the y direction. The battery module 100 is mounted on the vehicle. Therefore, the plurality of battery cells 11 included in the battery module 100 vibrate in the y direction due to the application of an external force such as vehicle vibration.

If the housing 31 is deformed in the y direction due to such expansion or vibration, the separation distances of the plurality of battery cells 11 in the y direction may change significantly. Due to this change, stress is generated at the connection portion between the negative electrode terminal 12 and the positive electrode terminal 13 in the series bus bar 14, and there is a possibility that an electrical connection failure may occur between the series bus bar 14 and the electrode terminal.

<Effect>
On the other hand, as described above, a plurality of battery cells 11 are arranged in the y direction between the first end wall 35 and the second end wall 36 of the housing 31. A rigid portion 42 having a higher rigidity than these end walls is connected to each of the first end wall 35 and the second end wall 36, which define the arrangement of the plurality of battery cells 11 in the y direction. The rigid portion 42 has a shape in which the length in the z direction is longer than the length in the x direction.

As a result, it is possible to prevent the opening side (tip side) of the housing 31 of each of the first end wall 35 and the second end wall 36 from being deformed in the y direction due to expansion or vibration of the battery cell 11. Therefore, it is possible to prevent the relative positions of the plurality of electrode terminals included in the first electrode terminal group or the second electrode terminal group from being significantly changed in the y direction due to the deformation of these end walls in the y direction.

As a result, it is possible to prevent stress from being generated at the connection portion between the negative electrode terminal 12, the positive electrode terminal 13, and the series bus bar 14 included in the electrode terminal group. It is possible to suppress the occurrence of electrical connection failure between the series bus bar 14 and the electrode terminals.

By suppressing the electrical connection failure, it is possible to prevent the power from being difficult to be output from the battery modules 100 connected in series of the plurality of battery cells 11. It is possible to prevent it from becoming difficult to supply electric power to various electric loads of the vehicle from an in-vehicle power source in which a plurality of battery modules 100 are connected in series or in parallel. As a result, the running failure of the electric vehicle is suppressed.

The rigid portion 42 extending in the z direction is aligned with the portion of the battery cell 11 passing through the center line CL in the y direction. According to this, the deformation of each of the first end wall 35 and the second end wall 36 is suppressed due to the expansion of the battery cell 11 having the midpoint CP as the apex in the y direction. As a result, the expansion of the battery cell 11 is suppressed.

The rigid portion 42 extending in the z direction is aligned with the portion of the battery cell 11 between the center line CL and the upper surface 11a in the y direction. As a result, the tip sides of the first end wall 35 and the second end wall 36 are prevented from being deformed in the y direction. As a result, the displacement of the upper surface 11a side of each of the plurality of battery cells 11 in the y direction is suppressed. As a result of stress acting on the electrode terminals formed on the upper surface 11a and the series bus bar 14 due to this displacement, it is possible to suppress the occurrence of electrical connection failure between the two.

The rigid portion 42 extending in the z direction is aligned with the protrusion 41 that fixes the position of the battery cell 11 in the storage space in the y direction. According to this, it is suppressed that the bottom wall 33 side of each of the first end wall 35 and the second end wall 36 is deformed by the vibration of the plurality of battery cells 11 due to the application of an external force. Due to the deformation of the bottom wall 33 side, the tip side of each of the first end wall 35 and the second end wall 36 is suppressed from being displaced in the y direction.

Between the rigid portion 42 of the first end wall 35 and the rigid portion 42 of the second end wall 36, a portion having the same position as the electrode terminal in the battery case of each of the plurality of battery cells 11 in the y direction is located. .. According to this, it is effectively suppressed that the electrode terminals of each of the plurality of battery cells 11 vibrate in the y direction due to an external force. Therefore, it is possible to effectively suppress the occurrence of electrical connection failure between the electrode terminal and the series bus bar 14.

Two rigid portions 42 are integrally connected to each of the first end wall 35 and the second end wall 36. At the same time, the two rigid portions 42 are integrally connected by the connecting portion 43. According to this, not only the rigidity of the connecting portion of the rigid portion 42 in each of the first end wall 35 and the second end wall 36 but also the rigidity of the connecting portion of the connecting portion 43 is effectively increased. Therefore, the deformation examples of the first end wall 35 and the second end wall 36 are effectively suppressed.

The connecting portion 43 is aligned with the midpoint CP of the battery cell 11 in the y direction. Therefore, deformation of the first end wall 35 and the second end wall 36 due to the expansion of the battery cell 11 having the midpoint CP as the apex in the y direction is effectively suppressed. The expansion of the battery cell 11 is effectively suppressed.

Each of the housing 31 and the lid 32 is made of a resin material having a melting point higher than that of the separator contained in the power generation element of the battery cell 11. According to this, even if the separator melts inside the battery case at the time of abnormal heat generation of the battery cell 11, it is suppressed that the housing 31 and the lid 32 melt. The melting of the housing 31 and the lid 32 prevents the plurality of battery cells 11 housed in the storage space partitioned by them from being unfixed. It is suppressed that the battery cell 11 in the abnormal heat generation state is exposed to the outside of the storage space.

The series bus bar 14 is formed by integrally connecting two terminal conductive portions 17 arranged apart from each other in the y direction via one connecting conductive portion 18. The connecting conductive portion 18 extends from one of the two terminal conductive portions 17 in the z direction, and then folds back and extends toward the other of the two terminal conductive portions 17 in the z direction.

Therefore, when the two terminal conductive portions 17 are displaced so as to be separated from each other in the y direction due to expansion of the battery cell 11 or the like, the length of the connected conductive portion 18 becomes the length in the y direction. It transforms in a way that it is converted. When the deformation of the connecting conductive portion 18 in which the length in the z direction is converted to the length in the y direction is completed, the stress generated at the connection portion of the terminal conductive portion 17 with the electrode terminal rapidly increases. As a result, there is a risk that an electrical connection failure may occur between the series bus bar 14 and the electrode terminals.

On the other hand, the length between the two terminal conductive portions 17 of the connecting conductive portion 18 is the gap between the plurality of battery cells 11 housed in the case 30 in the y direction, and the battery cells 11 and the case 30. It is longer than the total length of the gaps. Then, as described above, the deformation of each of the first end wall 35 and the second end wall 36 is suppressed.

Therefore, it is possible to prevent the two terminal conductive portions 17 from moving away in the y direction until the deformation in which the length in the z direction of the connecting conductive portion 18 is converted into the length in the y direction is completed. As a result, it is possible to prevent an electrical connection failure between the series bus bar 14 and the electrode terminal.

(First modification)
In the present embodiment, an example is shown in which the connecting portion 43 is connected (formed) to each of the first end wall 35 and the second end wall 36. However, the connecting portion 43 may not be connected to these end walls. Further, the number of connecting portions 43 connected to these end walls may be singular or plural as shown in the present embodiment.

For example, as shown in FIG. 13, two connecting portions 43 may be connected to the end wall. In the modified example shown in FIG. 13, the two connecting portions 43 extend in the inclined direction in which they are inclined in the z direction and the x direction, and the two are partially intersected. The intersection of the two connecting portions 43 is aligned with the midpoint CP in the y direction. In the modified example shown in FIG. 13, the negative electrode output terminal 34b and the positive electrode output terminal 34c are each connected to the end wall instead of the connecting portion 43.

(Second modification)
In the present embodiment, an example is shown in which two rigid portions 42 are integrally connected to each of the first end wall 35 and the second end wall 36. However, the number of rigid portions 42 connected to these end walls is not particularly limited. As the number of the rigid portions 42 connected to one end wall, a single number or three or more may be adopted.

(Third variant)
In the present embodiment, the rigid portion 42 extending continuously in the z direction passes through the protrusion 41, the portion of the battery cell 11 passing through the center line CL, the portion of the battery cell 11 between the center line CL and the upper surface 11a, and the y direction. An example of lining up with is shown. However, it is also possible to adopt a configuration in which the rigid portions 42 are not lined up in the y direction with any of these. Further, it is also possible to adopt a configuration in which the rigid portions 42 are aligned with some of them in the y direction.

For example, as shown in column (a) of FIG. 14, the rigid portion 42 is arranged in the y direction with each of the portion of the battery cell 11 passing through the center line CL and the portion of the battery cell 11 between the center line CL and the upper surface 11a. Can be adopted. As shown in column (b) of FIG. 14, it is possible to adopt a configuration in which the rigid portion 42 is aligned with the portion of the battery cell 11 between the center line CL and the upper surface 11a in the y direction.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various modifications and modifications within a uniform range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less are also included in the scope and ideology of the present disclosure. It is a thing.

10 ... Battery stack, 11 ... Battery cell, 12 ... Negative terminal, 13 ... Positive terminal, 14 ... Series bus bar, 30 ... Case, 31 ... Housing, 32 ... Lid, 33 ... Bottom wall, 34 ... Circular wall, 34h ... Inner end surface, 35 ... 1st end wall, 36 ... 2nd end wall, 37 ... 1st side wall, 38 ... 2nd side wall, 40 ... partition wall, 40a ... partition wall surface, 41 ... protrusion, 42 ... rigid part, 43 … Connecting part, 100… Battery module

Claims (11)

An insulating housing (31) including a bottom wall (33) and an annular wall (34) that rises from the bottom wall in an annular shape.
Each of the electrode terminals (12, 13) formed in the battery case in which the power generation element is housed is provided, and the electrode terminal is located closer to the tip end side of the annular wall than the bottom wall in the upright direction of the annular wall. At the same time, a plurality of battery cells (11) housed in the insulating housing in a manner of arranging in an arrangement direction orthogonal to the standing direction, and
A connection portion (14) for electrically connecting the electrode terminals of each of the plurality of battery cells,
It has a rigid portion (42) connected to the annular wall and
The annular wall is separated from the first end wall (35) and the second end wall (36) separated in the alignment direction, and the first end wall is separated in a lateral direction orthogonal to each of the standing direction and the alignment direction. It has a first side wall (37) and a second side wall (38) that connect the wall and the second end wall.
The forming material for each of the first end wall and the second end wall is a resin material.
A battery module in which the rigid portion has a higher rigidity than the resin material, and the length in the upright direction is longer than the length in the lateral direction. The battery module according to claim 1, wherein the position of a part of the rigid portion in the upright direction is the same as the position of the geometric center of the battery case in the upright direction. The battery module according to claim 1 or 2, wherein the position of a part of the rigid portion in the upright direction is closer to the tip end side of the annular wall in the upright direction than the geometric center of the battery case. The battery module according to any one of claims 1 to 3, wherein a part of the rigid portion is located on the bottom wall side in the standing direction with respect to the geometric center of the battery case. The battery module according to any one of claims 1 to 4, wherein the lateral position of a part of the rigid portion is the same as the lateral position of the electrode terminal. A plurality of the rigid portions are connected to each of the first end wall and the second end wall.
The battery module according to any one of claims 1 to 5, wherein a connecting portion (43) for integrally connecting a plurality of the rigid portions is connected to each of the first end wall and the second end wall. .. The battery module according to claim 6, wherein the position of a part of the connecting portion in the standing direction is the same as the position of the geometric center of the battery case in the standing direction. The battery module according to claim 6 or 7, wherein the lateral position of a part of the connecting portion is the same as the lateral position of the electrode terminal. In addition to the bottom wall and the annular wall, the insulating housing has a plurality of partition walls (40) arranged in the alignment direction between the first end wall and the second end wall.
The partition wall surface (40a) on the battery cell side of each of the plurality of partition walls and the inner end surface (34h) on the battery cell side of each of the first end wall and the second end wall are in the alignment direction. A locally protruding protrusion (41) is formed, and a protrusion (41) is formed.
The battery module according to any one of claims 1 to 8, wherein the battery cells are sandwiched by the protrusions in the arrangement direction. The battery according to claim 9, wherein the position of a part of the rigid portion in the upright direction is the same as the position of the protrusion formed on each of the first end wall and the second end wall in the upright direction. module. 9. or 10. The lateral position of a part of the rigid portion is the same as the lateral position of the protrusion formed on each of the first end wall and the second end wall. Battery module described in.

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